By now, in 2006, Java is up to version 1.5, with 1.6's release imminent. When the book was written in 2003, it necessarily used the then current Java, 1.4. But much of the book's advice is still germane. Remembering too that the various open source packages it describes are likely to be new revs as well.



The key idea in the text is to implement a simple concept in code. Only add complexity when it is truly needed. As a general rule in programming, or project design, this is important. It helps you more quickly make prototypes and test these in an agile fashion. Plus, once you have a stable code base, it is much easier for you or someone else to maintain.



The examples that use JUnit to implement an easy unit testing of your code are perhaps the most useful, to many readers. Unit testing greatly helps the robustness of your code. And the book correctly points out that it is not exclusively associated with Extreme Programming. Unit testing also is present in other methodologies.